Area Forecast Discussion
Issued by NWS Tucson, AZ

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050
FXUS65 KTWC 200425
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
925 PM MST Thu Oct 19 2017

.SYNOPSIS...A passing system will bring breezy conditions Friday and
cooler temperatures Saturday and Saturday night. Another strong high
pressure system will push temperatures rapidly back up, with near
record high temperatures expected the first half of next week.

&&

.DISCUSSION...IR/water vapor imagery depicted an area of mid and
high-level clouds generally from Tucson vicinity westward into
northern Baja California and far southern California at this time.
Meanwhile, mostly clear skies prevail across eastern sections. Based
on satellite trends, expect partly cloudy to mostly cloudy skies for
much of the area the rest of tonight. Clearing skies should then
occur from west-to-east perhaps starting as early as late tonight,
but especially Friday morning into early Friday.

Generally clear skies will likely prevail Friday afternoon into
Friday evening. Gusty southwest to northwest winds will also occur
late Friday morning into early Friday evening. High temperatures
Friday from Tucson westward will average about 5 degrees or so
cooler versus today, but temps Friday will mainly be unchanged
versus this afternoon across eastern sections.

The official forecast was updated earlier to remove any remaining
mention/depiction of showers for the rest of tonight. Please refer
to the additional sections for further detail.

&&

.AVIATION...Valid thru 21/06Z.
Expect a few clouds around 10k ft AGL and scattered to broken clouds
above 20k ft AGL into early Friday, then decreasing clouds from west
to east Friday afternoon. Clear skies should prevail most sections
late Friday afternoon and evening. Surface wind late Friday morning
and afternoon swly to nwly 12-20 kts with gusts near 30 kts (highest
speeds east of KTUS). Surface wind variable in direction less than
12 kts at other times. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Dry conditions into next Thursday. Expect gusty
southwest to northwest winds Friday into Saturday followed by
occasionally gusty east winds early next week.

&&

.CLIMATE...Record setting for Tucson with today being the 179th
day of 90+ degree high temperatures for 2017. This breaks the
record of 178 days which occurred in 1910 and 1989.

After a break over the weekend, record or near record high
temperatures are likely early next week as an unseasonably strong
ridge of high pressure aloft builds over the area. Current forecast
high of 97 for Tucson Intl next Tuesday would be the second latest
occurrence of 97 in the calendar on record. The record latest date
is Oct 27 2016. There is also a small chance next Tuesday that the
high at Tucson Intl could hit 98, which, if that happens, would be
the latest occurrence of 98 in the calendar on record, besting the
current latest date of Oct 19 in 1921 & 1991.

         Tucson International Airport
             Forecast  Record
Mon Oct 23      95       94
Tue Oct 24      97       96
Wed Oct 25      94       95

&&

.PREV DISCUSSION /321 PM MST/...A strong system currently pushing
into the Pacific Northwest from the Gulf of Alaska will dampen a bit
as it moves through the central and northern Great Basin. However,
it will pass through the region close enough to us to generate
breezy southwest to west winds Friday, followed by a frontal passage
Saturday that will push temperatures back to near or even a little
below average for a day.

Cooler overnight lows will also result, with Saturday night and
Sunday night into Monday morning the coolest nights. With the
frontal passage timing still not easy to pin down Saturday (probably
mid morning through late afternoon as it fragments through our
area), conditions may still be a little unsettled Saturday evening.
The drier air and lighter winds might be most evident Sunday night
into Monday morning, with overnight lows falling below average. That
means a few of the coldest valley spots in Cochise County (such as
Sulphur Springs Valley) may flirt with freezing.

A more amplified pattern will then bring a strong ridge from the
eastern Pacific building into California and Arizona early next
week. Forecast height and thickness values support near record
temperatures around 12 to 14 degrees above average Monday through
Wednesday. Please see the Climate section below for additional
details.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

Francis
PREVIOUS DISCUSSION...Meyer

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